When a man has Low T, it means his testosterone is below normal levels. It's natural for men to produce less testosterone as they age. However, it's not natural for testosterone to fall below a certain level. When a man's testosterone falls below a level of around 300 ng/dL, it's generally considered to be low.
What causes low testosterone? Low T can happen when there is a signaling problem between the brain and the testes that causes a drop in the amount of testosterone that is being produced. Also, if the brain feels that there is too much testosterone in the body, it can signal the testes to cut production. Another reason Low T can occur is that your body simply can't produce enough testosterone due to a defect in the testes.
Low T is a medical condition known as hypogonadism. Your doctor can tell if you have hypogonadism by giving you a medical exam to assess your signs and symptoms, then performing blood tests. Your doctor can also decide if treatment options such as testosterone replacement therapy (TRT) could help bring the T levels back to normal.